Accumulator

An accumulator comprising:

• an accumulator housing which is provided with an oil port connected to a pressure piping and is provided with a gas charging port in an end portion at an opposite side;
• a stay which is arranged at an inner side of said oil port within said housing and is provided with a liquid passage in an end surface portion on an end of a stepped tubular portion;
• a bellows which is arranged within said housing, is provided with a bellows cap on a floating end and comparts a space within said housing into a gas chamber being charged with a gas and a liquid chamber communicating with said oil port;
• a safety mechanism for a pressure drop time which confines a part of liquid in said liquid chamber on the basis of sealing between said bellows cap or a member retained by said bellows cap and the end surface portion of said stay at a time when pressure of said liquid chamber is lowered in accordance with a pressure drop of said pressure piping;
• and
• a safety mechanism for an emergency time which opens said liquid chamber on the basis of buckling of said stay due to a step of said stepped tubular portion by said bellows cap or the member retained by said bellows cap pressing said stay in response to housing internal pressure which becomes higher pressure at an emergency time such as a fire occurrence or the like, wherein the step of said stay is provided circumferentially partially with a thin portion so that the end surface portion of said stay readily inclines at a time when said bellows cap presses said stay and said stay buckles due to said step at said emergency time.